Atmel CAVR-4 Manuale Utente

CAVR-4

Part 2. Compiler reference

--root_variables

--root_variables

Use this option to apply the 

_ _root

 extended keyword to all global and static variables. 

This will make sure that the variables are not removed by the IAR XLINK Linker.

Notice that the 

--root_variables

 option is always available, even if you do not 

specify the compiler option 

-e

, language extensions. 

This option is related to the Code options in the C/C++ Compiler category in IAR 
Embedded Workbench.

-s

-s[2|3|6|9] 

Use this option to make the compiler optimize the code for maximum execution speed. 

If no optimization option is specified, the compiler will use the size optimization 

-z2

 

by default. If the 

-s

 option is used without specifying the optimization level, speed 

optimization at level 2 is used by default. 

The following table shows how the optimization levels are mapped:

-s2

-s3

A low level of optimization makes it relatively easy to follow the program flow in the 
debugger, and, conversely, a high level of optimization makes it relatively hard.

Note: The 

-s

 and 

-z

 options cannot be used at the same time. 

To set the equivalent option in IAR Embedded Workbench, select 
Project>Options>C/C++ Compiler>Code.

--segment

--segment memory_attribute=segment_name

Use this option to place all variables or functions with the memory attribute 

 in segments with names that begin with 

. 

For example, the following command places the 

_ _near int a;

 variable in the 

FOO_Z

 

segment:

--segment _ _near=FOO

2

None* (Best debug support)

3

Low*

6

Medium

9

High (Maximum optimization)